The Magic: the Gathering Standard Best of 1 Format in Magic Arena is one of my preferred modes because of the lack of card components in my original account’s card pool. The advantage is if you win, the opponent has no chance to get back with the sideboarded games. That is also the drawback if you get to face a deck that has more edge than your build. Anywho, I can say that this is the best mode to grind fast your rank if you get to build the best deck fitted for the BO1 gameplay.